Background/Objectives The inoculation of a minimal number (104) of metacyclic promastigotes into the dermis of C57BL/6 and DBA/2 mouse ear pinna results in unique outcome as assessed from the parasite weight values and ear pinna macroscopic features monitored from days 4 to 22-phase 1 and from days 22 to 80/100-phase 2. display unique transcriptional signatures and markers that could contribute to the unique features observed in C57BL/6 versus DBA/2 ear pinna and in the ear pinna-DLNs during the 1st phase post inoculation. Conclusions/Significance The unique features captured from homogenous populations of C57BL/6 and DBA/2 DLs hosting live amastigotes do offer solid resources for further comparing, metacyclic promastigotes completed their four day time developmental system along the amastigote morphotype. Intro perpetuates in South and Central America, its main location being the damp forests of the Amazon basin. The perpetuation of this species BMS-477118 relies successively on two hosts which cohabit more or less transiently within this ecosystem: blood-feeding sand flies and mammals, including crazy rodents and humans. A broad spectrum of medical manifestations, ranging from solitary cutaneous lesions to multiple, disfiguring nodules [1], [2], [3] assess the durable establisment of as intracellular amastigotes in the dermis. As model rodents, the laboratory CENP-31 mice of different inbred strains can be subverted as hosts by inoculation and in multiple pores and skin sites reached by parasites emigrating from the primary inoculation site [4], [5], [6], [7], [8]. By contrast, in DBA/2 mice, in the inoculation site, the population size is definitely rapidly controlled, a process coupled to a controlled inflammatory process BMS-477118 with limited parasite dissemination in distant cells(s), if any [9]. Realizing that once in the dermis of the mouse, amastigotes are hosted by mononuclear phagocytes including macrophages and dendritic BMS-477118 leukocytes (DLs) [10], [11], [12], [13], [14], [15], we have addressed the following query: could the DLs harbouring live amastigotes contribute to the unique phenotypes observed in C57BL/6 and DBA/2 mice? Since the rate of recurrence of DLs hosting live amastigotes within the skin and skin-draining lymph nodes (DLNs) remains very low [16], [17] we decided to 1st conduct an study relying on bone marrow-derived DLs (BMD-DLs) from C57BL/6 and DBA/2 mice revealed or not to live amastigotes. Based on circulation cytometry (FCM), genechip (Affymetrix Mouse GeneChip) and real-time quantitative PCR (RT-qPCR) analyses performed on sorted DLs hosting live transgenic amastigotes [17] many unique features have been highlighted. DBA/2 DLs displayed transcriptional markers and signatures that may be related to the early phenotype observed protective niche. Altogether this research provides, for the first time, a solid base for exploring i) the inflammatory processes that maintain the amastigote population under control in DBA/2 mice and ii) the inflammatory processes coupled to extended parasite dissemination and to poor parasite population control in C57BL/6 mice. Methods Mice Six week old female DBA/2, C57BL/6 and Swiss mice were purchased from Charles River (Saint Germain-sur-l’Arbresle, France). Ethics statement All animals were housed in our A3 animal facilities in compliance with the guidelines of the A3 animal facilities at the Pasteur Institute which is a member of Committee 1 of the Comit d’Ethique pour l’Exprimentation Animale (CEEA) – Ile de France – Animal housing conditions and the protocols used in the work described herein were approved by the Direction BMS-477118 des Transports et de la Protection du Public, Sous-Direction de la Protection Sanitaire et de l’Environnement, Police Sanitaire des Animaux under number B75-15-28 in accordance with the Ethics Charter of animal experimentation that includes appropriate procedures to minimize pain and animal suffering. TL is authorized to perform experiment on vertebrate BMS-477118 animals (licence 75-717) issued by the Paris Department of Veterinary Services, DDSV) and is responsible for all the experiments conducted personally or under his supervision as governed by the laws and regulations relating to the protection of animals. Preparation of amastigotes and metacyclic promastigotes strain LV79 (WHO reference number MPRO/BR/72/M1841) amastigotes were isolated from Swiss nude mice inoculated 2 months before within a BSL-2 cabinet space as described previously [17]. These amastigotes did not present any antibodies at their surface [18]. Promastigotes derived from amastigotes were cultured at 26C in complete M199 medium. The metacyclic promastigote.